#pragma once

namespace lh
{
	template<class T, class Container = vector<T>,class Compare=std::less<T>>
	class priority_queue
	{
	public:
		priority_queue()
		{}
		template<class InputIterator>
		priority_queue(InputIterator first, InputIterator last)
		{
			while (first != last)
			{
				_con.push_back(*first);
				++first;
			}
			//建堆,(_con.size()-1-1)/2为末尾节点的父节点所在位置
			for (int i = ((_con.size() - 1 - 1) / 2); i >= 0; i--)
			{
				//向下建堆logN
				adjust_down(i);
			}
		}
		//向上建堆
		void adjust_up(size_t child)
		{
			/*size_t parent = (child - 1) / 2;
			while (child > 0)
			{
				//建大堆
				if (_con[parent] < _con[child])
				{
					std::swap(_con[parent], _con[child]);
					child = parent;
					parent = (child - 1) / 2;
				}
				else
				{
					break;
				}
			}*/
			Compare com;//仿函数，类对象像函数一样使用，重载operator()
			size_t parent = (child - 1) / 2;
			while (child > 0)
			{
				//建大堆
				if (com(_con[parent],_con[child]))
				{
					std::swap(_con[parent], _con[child]);
					child = parent;
					parent = (child - 1) / 2;
				}
				else
				{
					break;
				}
			}
		}
		void push(const T& x)
		{
			_con.push_back(x);

			adjust_up(_con.size() - 1);
		}
		//向下建堆
		void adjust_down(size_t parent)
		{
			/*size_t child = parent * 2 + 1;
			while (child < _con.size())
			{
				//选出左右孩子大的那一个
				if (child + 1 < _con.size() && _con[child] < _con[child + 1])
				{
					++child;
				}
				//建大堆
				if (_con[parent] < _con[child])
				{
					std::swap(_con[parent], _con[child]);
					parent = child;
					child = parent * 2 + 1;
				}
				else
				{
					break;
				}
			}*/
			Compare com;//仿函数，类对象像函数一样使用，重载operator()
			size_t child = parent * 2 + 1;
			while (child < _con.size())
			{
				//选出左右孩子大的那一个
				if (child + 1 < _con.size() && com(_con[child] , _con[child + 1]))
				{
					++child;
				}
				//建大堆
				if (com(_con[parent] , _con[child]))
				{
					std::swap(_con[parent], _con[child]);
					parent = child;
					child = parent * 2 + 1;
				}
				else
				{
					break;
				}
			}
		}
		void pop()
		{
			std::swap(_con[0], _con[_con.size() - 1]);
			_con.pop_back();

			adjust_down(0);
		}
		const T& top() const
		{
			return _con[0];
		}
		bool empty() const
		{
			return _con.empty();
		}
		size_t size() const
		{
			return _con.size();
		}
	private:
		Container _con;
	};
}